A liquid crystal display device is used for various equipments such as a television set, a car navigation equipment, a mobile terminal equipment, for example, a notebook PC and a cellular phone.
For example, in the liquid crystal display device in TN (Twisted Nematic) mode or OCB (Optically Compensated Bend) mode, a liquid crystal layer is held between a counter electrode formed on an upper side substrate and pixel electrodes formed on a lower side substrate, and the direction of alignment of the liquid crystal molecule contained in the liquid crystal layer is controlled by electrical field impressed between the counter electrode and the pixel electrodes.
Moreover, in the liquid crystal display device in IPS (In-Plane Switching) mode or FFS (Fringe-Field Switching) mode, both the counter electrode (COM electrode) and the pixel electrodes are formed on one of the substrates, and the direction of the alignment of the liquid crystal molecule contained in the liquid crystal layer is controlled by electrical field (fringe electrical field) impressed between both electrodes (for example, referring to Japanese Laid Open Patent Application No. 2002-014363). Since the liquid crystal display device in the FFS mode can secure a large aperture ratio, the liquid crystal display device achieves high brightness and excellent viewing angle characteristics.
In the liquid crystal display device in the above FFS mode, image sticking phenomenon may occur. The meaning of the image sticking phenomenon is as follows: if a gray picture (half tone picture) is displayed on a full screen after displaying a monochrome checkered pattern for a while, the pale checkered pattern remains like an incidental image.